Down-regulation of ACE2 in the placenta due to SARS-CoV-2 may lead to oxidative stress of the placenta and the release of anti-angiogenic factors, including soluble fms-like tyrosine kinase-1 (sFlt-1) (50), and a decrease in pro-angiogenic factors, leading to features of pre-eclampsia and HELLP syndrome (49). This evidence concerns the gene FLT1 and HELLP syndrome.